SBAA275A June 2018 – March 2023 ADS1120 , ADS112C04 , ADS112U04 , ADS1147 , ADS1148 , ADS114S06 , ADS114S06B , ADS114S08 , ADS114S08B , ADS1220 , ADS122C04 , ADS122U04 , ADS1247 , ADS1248 , ADS124S06 , ADS124S08 , ADS125H02 , ADS1260 , ADS1261 , ADS1262 , ADS1263
RTDs, or resistance temperature detectors, are sensors used to measure temperature. These sensors are the among the most accurate temperature sensors available, covering large temperature ranges. However, getting accurate measurements with precision analog-to-digital converters (ADCs) requires attention to detail in design of measurement circuits and calculation of the measurement. This application note starts with an overview of the RTD, discussing their specifications, construction, and details in their use in temperature measurement. Different circuit topologies with precision ADCs are presented for different RTD configurations. Each circuit is shown with a basic design guide, showing calculations necessary to determine the ADC settings, limit measurement errors, and verify that the design fits in the operating range of the ADC.